DL 1223 then DL 726 at Atlanta
Cincinnati → Atlanta → Boston
Timetable, Atlanta time
16:30DL 1223 from Cincinnati at the gate
13:50DL 726 to Boston leaves the gate
21 h 20 apart on the timetable, overnight
DL 726 leaves 21 h 20 after DL 1223 arrives on the timetable: more than half a day, so not a connection we count.