What date has a competition of 2012 afc challenge cup, and dasarath rangasala stadium, kathmandu as the venue?
CREATE TABLE "international_goals" (
  "date" text,
  "venue" text,
  "score" text,
  "result" text,
  "competition" text
);
SELECT "date" FROM "international_goals" WHERE "competition"='2012 afc challenge cup' AND "venue"='dasarath rangasala stadium, kathmandu';