CREATE TABLE "wins_15" (
  "date" text,
  "tournament" text,
  "surface" text,
  "opponent_in_final" text,
  "score_in_final" text
);

Question: What is Date, when Opponent in Final is "Guy Forget"?
SQL: SELECT "date" FROM "wins_15" WHERE "opponent_in_final"='guy forget';

Question: What is Opponent in Final, when Date is "13 January 1992"?
SQL: SELECT "opponent_in_final" FROM "wins_15" WHERE "date"='13 january 1992';

Question: What is Opponent in Final, when Surface is "Hard", and when Date is "13 January 1992"?
SQL: SELECT "opponent_in_final" FROM "wins_15" WHERE "surface"='hard' AND "date"='13 january 1992';