UA 3913 then UA 722 at Houston
Denver → Houston → Columbus (Ohio)
Timetable, Houston time
21:22UA 3913 from Denver at the gate
12:10UA 722 to Columbus (Ohio) leaves the gate
14 h 48 apart on the timetable, overnight
UA 722 leaves 14 h 48 after UA 3913 arrives on the timetable: more than half a day, so not a connection we count.