CREATE TABLE "previous_winners" (
  "year" text,
  "men_s_singles" text,
  "women_s_singles" text,
  "men_s_doubles" text,
  "women_s_doubles" text,
  "mixed_doubles" text
);

Question: What is the year when Conrad Hückstädt won Men's Single?
SQL: SELECT "year" FROM "previous_winners" WHERE "men_s_singles"='conrad hückstädt';

Question: Who won the Men's Double the same year as Florentina Petre winning the Women's Singles?
SQL: SELECT "men_s_doubles" FROM "previous_winners" WHERE "women_s_singles"='florentina petre';

Question: In what year was there no competition for women?
SQL: SELECT "year" FROM "previous_winners" WHERE "women_s_singles"='no competition';