A Democrat wins the last pending election in the US House of Representatives by 187 votes.

()— Republican Rep. John Duarte acknowledged his defeat to his Democratic opponent Adam Gray in California’s 13th congressional district, Duane Dichiara, spokesperson for Duarte’s campaign, confirmed to .

All five counties in this district certified their results on Tuesday, leaving Gray with a 187-vote lead.

This race was the last unresolved race in the United States House of Representatives. With Gray’s victory, Republicans are left with 220 seats compared to 215 for Democrats. In sum, the Democrats gained one seat compared to the total they had before the elections.

The Republican majority is likely to be even tighter early next year: Former Republican Rep. Matt Gaetz of Florida resigned from the House last month and will not take his seat in the new Congress. Additionally, Republican Reps. Elise Stefanik of New York and Mike Waltz of Florida are expected to leave the House for positions in Donald Trump’s administration.

If all three seats become vacant at the same time, a 217-215 majority would mean Republicans could not afford to lose a single member in a vote that needs party-wide support.