AA 4708 then DL 5704 at Boston
Harrisburg → Boston → Washington National
Timetable, Boston time
08:34AA 4708 from Harrisburg at the gate
21:45DL 5704 to Washington National leaves the gate
13 h 11 apart on the timetable
DL 5704 leaves 13 h 11 after AA 4708 arrives on the timetable: more than half a day, so not a connection we count.