Table: atp_1993_tour
Columns: week_of
tournament
champions
runners_up
semifinalists

Question: Which Semifinalists has a Champions of michael chang 6-0 6-4?
SQL: SELECT "semifinalists" FROM atp_1993_tour WHERE "champions" = 'michael chang 6-0 6-4'

Question: Whose Runner-up has a Semifinalist of guillermo pérez-roldán andrea gaudenzi?
SQL: SELECT "runners_up" FROM atp_1993_tour WHERE "semifinalists" = 'guillermo pérez-roldán andrea gaudenzi'