If the stadium name is the Thuwunna Stadium, what is the date?
CREATE TABLE "2011_2012" (
  "date" text,
  "tournament" text,
  "location" text,
  "opponent" text,
  "stadium" text,
  "score" text,
  "indian_scorers" text
);
SELECT "date" FROM "2011_2012" WHERE "stadium"='Thuwunna Stadium';