Who won the mixed doubles when ji xinpeng won the mens singles?
CREATE TABLE "table1_12027364_1" (
  "year" real,
  "mens_singles" text,
  "womens_singles" text,
  "mens_doubles" text,
  "womens_doubles" text,
  "mixed_doubles" text
);
SELECT "mixed_doubles" FROM "table1_12027364_1" WHERE "mens_singles"='Ji Xinpeng';