state the number of surface where championship is australian open and score in the final is 6–3, 4–6, 11–9
CREATE TABLE "mixed_doubles_7_5_titles_2_runner_ups" (
  "outcome" text,
  "year" real,
  "championship" text,
  "surface" text,
  "partner" text,
  "opponents_in_the_final" text,
  "score_in_the_final" text
);
SELECT COUNT("surface") FROM "mixed_doubles_7_5_titles_2_runner_ups" WHERE "championship"='Australian Open' AND "score_in_the_final"='6–3, 4–6, 11–9';