DL 2503 then UA 5539 at O'Hare
New York LaGuardia → Chicago → Cleveland
Timetable, Chicago time
19:25DL 2503 from New York LaGuardia at the gate
10:50UA 5539 to Cleveland leaves the gate
15 h 25 apart on the timetable, overnight
UA 5539 leaves 15 h 25 after DL 2503 arrives on the timetable: more than half a day, so not a connection we count.