DL 776 then DL 5615 at Boston
Miami → Boston → Louisville
Timetable, Boston time
23:33DL 776 from Miami at the gate
12:15DL 5615 to Louisville leaves the gate
12 h 42 apart on the timetable, overnight
DL 5615 leaves 12 h 42 after DL 776 arrives on the timetable: more than half a day, so not a connection we count.