As of 10 p.m., 34 of 34 precincts in Comal, 91 of 91 precincts in Hays and 157 of 258 precincts in Bexar had reported results.
Reports show Zapata leading with 62.37% of the vote, or 10,130 votes, and Ricardo Villarreal has 37.63%, or 6,111 votes.
The Democratic winner of the primary election for the seat will advance to the general election in November. The victor will face Republican incumbent Chip Roy in the general election.
Election results are unofficial until they are canvassed and certified.
