LOS ANGELES — Three Democrats led the pack Wednesday of 13 candidates seeking an open Los Angeles-area seat in the California Assembly, but the race remained too close to call.

Los Angeles County officials plan to share an update on the vote count Friday, said Brenda Duran, a spokeswoman for the county clerk’s office. The top two vote-getters will advance to a runoff in December.

Wendy Carrillo, a former union organizer and journalist, was leading with 21 percent of the vote. She was closely trailed by Luis Lopez, with 19 percent of the vote. He ran for the seat in 2012 but lost. Mike Fong, a community college board member, is in third place with 16.6 percent of the vote.

“We are excited to congratulate the top two (vote) getters when the time comes and the counting is ultimately completed,” Los Angeles County Democratic Party Vice Chairman Mark Gonzalez said in a statement.

A Democratic victory in the 51st Assembly District will again give the party 55 out of 80 Assembly seats, tightening its grip on the supermajority needed to pass tax and fee increases. Democrats also hold a supermajority in the Senate.

The seat opened when Democrat Jimmy Gomez, a former assemblyman, was elected to Congress after U.S. Rep. Xavier Becerra became state attorney general. Tuesday’s special election was the fourth in northeastern Los Angeles since last November.

Gomez endorsed Carrillo on Wednesday, potentially giving her an edge if she remains one of the two candidates headed to the run-off. Carrillo previously ran against Gomez for the congressional seat.

“With the Trump Administration continuing to target our communities, I know Wendy will be a champion for our families in the fight for quality education, better healthcare, affordable housing, high wage jobs and protecting our most vulnerable residents including women, seniors, and immigrants,” Gomez said in a statement provided by Carrillo’s campaign.

The district is one of the most solidly Democratic Assembly seats, with large Latino and LGBT voting blocks.

Carrillo, an immigrant from El Salvador, became a legal resident of the United States at age 13. She has the backing of the legislative Women’s Caucus as well as Emily’s List, a national organization that supports Democratic women.

Lopez, an openly gay man, has been endorsed by Equality California, an LGBT rights group.

Fong sits on the board of the Los Angeles Community College District.

Paul Mitchell of Political Data, a firm that provides voting data to candidates, said mail-in ballots and provisional ballots that haven’t been counted could change the vote standing.