SACRAMENTO, Calif. (AP) — Fewer than 200 votes separate two candidates in a tighter-than-expected runoff election to represent a Southern California district in the state Assembly.

Democrat Matt Dababneh, a top aide to U.S. Rep. Brad Sherman, held a slim lead Wednesday with 13,309 votes to Republican Susan Shelley's 13,136. Elections officials in Los Angeles and Ventura counties said 2,842 ballots remained uncounted in the heavily Democratic district.

Democrats are counting on Dababneh to fill the vacant seat to restore their two-thirds supermajority in the 80-member Assembly.

Shelley has the backing of the Howard Jarvis Taxpayers Association. She positioned her candidacy as essential to blocking Democrats from the margin they need to raise taxes or tinker with Proposition 13, the 1978 initiative that rolled back property tax levels and put a cap on how much they could rise each year.

"Voters are over-taxed and tired of it," Shelley said in a telephone interview. "The politicians in Sacramento are attacking Prop. 13 ... and I said I will vote no on all of that, and voters are with me."

Some Democratic lawmakers have proposed changes to the landmark law in the past, including ending or modifying the provisions applying to commercial properties, but the party's legislative leaders so far have not advocated for such reforms. They are not likely to do so anytime soon, said Steve Maviglio, spokesman for Assembly Speaker John Perez, D-Los Angeles.

"She will be just as likely to find Sasquatch as she will attempts by the Legislature to tinker with Proposition 13," he said.

Shelley credited the state's top-two primary system for giving her a chance in the election. Shelley, who describes herself as socially moderate, said she probably would not have survived a traditional Republican primary.

She credited her strong showing to her appeal with Democrats and independent voters.

Dababneh and his aides did not return telephone messages Wednesday.

The District 45 seat became vacant this summer when incumbent Bob Blumenfield, a Democrat, resigned after winning election to the Los Angeles City Council.

Dababneh had been favored because Democrats have a 49 percent to 25 percent voter registration edge over Republicans. About 1 in 5 voters has no party preference. The Democrat also raised more campaign money than Shelley.

Dababneh finished first in a crowded primary field in September, winning 25 percent of the vote. Shelley, an author and former congressional candidate, advanced to the runoff with 21 percent support.

District 45 includes the southwest San Fernando Valley communities of Encino, Northridge and West Hills, as well as the cities of Calabasas and Hidden Hills, all in Los Angeles County. It also includes a sliver of Ventura County.

Less than 11 percent of voters turned out in Los Angeles County, where most of the district lies. Nearly 27,000 ballots were counted on election night. Ventura County had a similar turnout, with 149 ballots cast among the 1,359 eligible voters.

Election officials in both counties said they expect to have all the outstanding provisional and vote-by-mail ballots counted by Nov. 29.