DL 4654 then DL 537 at Atlanta
Knoxville → Atlanta → Washington National
Timetable, Atlanta time
09:44DL 4654 from Knoxville at the gate
21:59DL 537 to Washington National leaves the gate
12 h 15 apart on the timetable
DL 537 leaves 12 h 15 after DL 4654 arrives on the timetable: more than half a day, so not a connection we count.