FR 803 then OS 645 at Vienna
Valencia → Vienna → Prague
Timetable, Vienna time
21:45FR 803 from Valencia at the gate
15:20OS 645 to Prague leaves the gate
17 h 35 apart on the timetable, overnight
OS 645 leaves 17 h 35 after FR 803 arrives on the timetable: more than half a day, so not a connection we count.