WHAT IS THE NAME OF THE MIXED DOUBLES PLAYER WHEN THE WOMENS SINGLE PLAYER IS KAIRI VIILUP?
CREATE TABLE "past_winners" (
  "year" real,
  "mens_singles" text,
  "womens_singles" text,
  "mens_doubles" text,
  "womens_doubles" text,
  "mixed_doubles" text
);
SELECT "mixed_doubles" FROM "past_winners" WHERE "womens_singles"='Kairi Viilup';