UA 315 then UA 3907 at Houston
Tucson → Houston → Washington
Timetable, Houston time
10:53UA 315 from Tucson at the gate
07:00UA 3907 to Washington leaves the gate
20 h 07 apart on the timetable, overnight
UA 3907 leaves 20 h 07 after UA 315 arrives on the timetable: more than half a day, so not a connection we count.