For edition is 2011 europe/africa group iiib and surface where score is 6–4, 6–1 please specify all the surface
CREATE TABLE "singles" (
  "outcome" text,
  "edition" text,
  "opponent_team" text,
  "surface" text,
  "opponent" text,
  "score" text
);
SELECT "surface" FROM "singles" WHERE "score"='6–4, 6–1' AND "edition"='2011 Europe/Africa Group IIIB';