Jelly, 87 bytes
ẆŒPe@\ƇḢẆŒPi\ƇḢ
-1 byte thanks to Unrelated String
ẆŒPe@\ƇḢẆŒPi\ƇḢ Main Link
Ḣ Find the first
Ẇ slice (ordered by length)
Ƈ where
e@i the right listlist's index is truthy (occurs in)
ŒP the powerset (stable ordered)
1-indexing saves me a byte, thank you Dennis!
Jelly, 8 bytes
ẆŒPe@\ƇḢ
ẆŒPe@\ƇḢ Main Link
Ḣ Find the first
Ẇ slice (ordered by length)
Ƈ where
e@ the right list occurs in
ŒP the powerset (stable ordered)
Jelly, 7 bytes
ẆŒPi\ƇḢ
-1 byte thanks to Unrelated String
ẆŒPi\ƇḢ Main Link
Ḣ Find the first
Ẇ slice (ordered by length)
Ƈ where
i the right list's index is truthy (occurs in)
ŒP the powerset (stable ordered)
1-indexing saves me a byte, thank you Dennis!
Jelly, 8 bytes
ẆŒPe@\ƇḢ
ẆŒPe@\ƇḢ Main Link
Ḣ Find the first
Ẇ slice (ordered by length)
Ƈ where
e@ the right list occurs in
ŒP the powerset (stable ordered)