On what date was Keiichi Ubukata the mediator and Mitsuko Mori the red team host?
CREATE TABLE "table1_1315616_1" (
  "k_haku_num" real,
  "date" text,
  "red_team_host" text,
  "white_team_host" text,
  "mediator" text,
  "winning_team" text
);
SELECT "date" FROM "table1_1315616_1" WHERE "mediator"='Keiichi Ubukata' AND "red_team_host"='Mitsuko Mori';