InsiderMississippi is holding Republican House primary runoffs in three districts. Polls close at 7 p.m. local time. Mississippi Republican runoffs:3rd Congressional District:It's a competition of the two Michaels in Mississippi's 3rd Congressional District. Incumbent Michael Guest and political newcomer Michael Cassidy will go head-t0-head for the Republican nomination after neither candidate earned the 50% of votes necessary to claim it outright.