My husband says that was the 1979/80 season. Hull City were also in the 3rd Division and played Sheffield Wednesday in the League Cup losing on aggregate.
they have only ever played once before at this level. they were played in the 1979/80 season with wednesday winning 4-0 at hillsborough on boxing day 1979 in front of a record crowd for this division of 49,306. the return match played at easter at bramall lane in front of 46,000+ with united holding out for a 1-1 draw. i cannot see these attendance records ever being broken.