What is the name of the opponent when anastasia pivovarova was the partner?
CREATE TABLE "doubles_finals_2_4" (
  "outcome" text,
  "date" text,
  "tournament" text,
  "surface" text,
  "partner" text,
  "opponents" text,
  "score" text
);
SELECT "opponents" FROM "doubles_finals_2_4" WHERE "partner"='anastasia pivovarova';