Table: euro_cup_1991_92
Columns: season
round
opponents
home_leg
away_leg
aggregate

Question: What is the home leg who are opponents of rotor volgograd
SQL: SELECT "home_leg" FROM euro_cup_1991_92 WHERE "opponents" = 'rotor volgograd'

Question: What is the round with ajax opponents
SQL: SELECT "round" FROM euro_cup_1991_92 WHERE "opponents" = 'ajax'