AA 1951 then DL 5704 at Boston
Chicago O'Hare → Boston → Washington National
Timetable, Boston time
09:29AA 1951 from Chicago O'Hare at the gate
21:45DL 5704 to Washington National leaves the gate
12 h 16 apart on the timetable
DL 5704 leaves 12 h 16 after AA 1951 arrives on the timetable: more than half a day, so not a connection we count.