When did Chetan Anand win his first men's single?
CREATE TABLE "previous_winners" (
  "year" real,
  "mens_singles" text,
  "womens_singles" text,
  "mens_doubles" text,
  "womens_doubles" text,
  "mixed_doubles" text
);
SELECT MIN("year") FROM "previous_winners" WHERE "mens_singles"='Chetan Anand';