Name the number of years for womens doubles being  diana koleva emilia dimitrova and  jeliazko valkov
CREATE TABLE "past_winners" (
  "year" real,
  "mens_singles" text,
  "womens_singles" text,
  "mens_doubles" text,
  "womens_doubles" text,
  "mixed_doubles" text
);
SELECT COUNT("year") FROM "past_winners" WHERE "womens_doubles"='Diana Koleva Emilia Dimitrova' AND "mens_singles"='Jeliazko Valkov';