UA 3910 then UA 722 at Houston
Washington → Houston → Columbus (Ohio)
Timetable, Houston time
14:30UA 3910 from Washington at the gate
12:10UA 722 to Columbus (Ohio) leaves the gate
21 h 40 apart on the timetable, overnight
UA 722 leaves 21 h 40 after UA 3910 arrives on the timetable: more than half a day, so not a connection we count.