What was the score of the match on April 23, 2007?
CREATE TABLE "doubles_runner_ups_6" (
  "date" text,
  "tournament" text,
  "surface" text,
  "partnering" text,
  "opponents_in_the_final" text,
  "score" text
);
SELECT "score" FROM "doubles_runner_ups_6" WHERE "date"='april 23, 2007';