DL 1020 then DL 5610 at Boston
Washington National → Boston → Philadelphia
Timetable, Boston time
08:37DL 1020 from Washington National at the gate
20:40DL 5610 to Philadelphia leaves the gate
12 h 03 apart on the timetable
DL 5610 leaves 12 h 03 after DL 1020 arrives on the timetable: more than half a day, so not a connection we count.