SG 621 then SG 622 at Mumbai
Udaipur → Mumbai → Varanasi
Timetable, Mumbai time
12:55SG 621 from Udaipur at the gate
10:40SG 622 to Varanasi leaves the gate
21 h 45 apart on the timetable, overnight
SG 622 leaves 21 h 45 after SG 621 arrives on the timetable: more than half a day, so not a connection we count.