A runoff election will determine the Republican candidate for the redrawn Congressional District 25.

Roger Williams will go up against Wes Riddle in the July 31 runoff. In the primary race with a dozen candidates, Roger Williams had 25 percent of the vote, and Michael Williams had 15 percent of the vote, according to unofficial results.

The nearest challenger was Justin Hewlett with 12 percent of the vote.

Congressional District 25 has been held by U.S. Rep. Lloyd Doggett, D-Austin, since 2005. But after the congressional map was redrawn to become more Republican and cover part of Travis County and stretch north to Fort Worth, Doggett decided to run for a different district.

The winner of the Republican runoff will take on Democrat Elaine Henderson in the general election.

Correction: The original article incorrectly stated that Roger Williams would take on Michael Williams in the runoff.