Table: grey_cup_broadcasts_3
Columns: year
network
play_by_play
colour_commentator_s
pregame_host

Question: For which network was Chris Walby the color commentator after 1990?
SQL: SELECT "network" FROM grey_cup_broadcasts_3 WHERE "year" > 1990 AND "colour_commentator_s" = 'chris walby'

Question: Who was the pregame host before 1992 when there was a play by play of Bob Irving?
SQL: SELECT "pregame_host" FROM grey_cup_broadcasts_3 WHERE "year" < 1992 AND "play_by_play" = 'bob irving'