Who were the opponents for the event in Milan, Italy?
CREATE TABLE "doubles_35_20_15" (
  "outcome" text,
  "date" text,
  "tournament" text,
  "surface" text,
  "partnering" text,
  "opponent" text,
  "score" text
);
SELECT "opponent" FROM "doubles_35_20_15" WHERE "tournament"='milan, italy';