Name the winners of the mens doubles in the season of 1963/64.
CREATE TABLE "senior_events" (
  "season" text,
  "mens_singles" text,
  "womens_singles" text,
  "mens_doubles" text,
  "womens_doubles" text,
  "mixed_doubles" text
);
SELECT "mens_doubles" FROM "senior_events" WHERE "season"='1963/64';