Table: tournaments
Columns: date
tournament
surface
opponent_in_the_final
score

Question: On what type of surface did they play on 13 February 1994?
SQL: SELECT "surface" FROM tournaments WHERE "date" = '13 february 1994'

Question: In which tournament was Silke Meier the opponent in the final?
SQL: SELECT "tournament" FROM tournaments WHERE "opponent_in_the_final" = 'silke meier'