What was the 2nd leg fo the match that had a 1st leg of 1-3 and aggregate of 1-6?
CREATE TABLE "round_of_sixteen" (
  "team_1" text,
  "agg" text,
  "team_2" text,
  "1st_leg" text,
  "2nd_leg" text
);
SELECT "2nd_leg" FROM "round_of_sixteen" WHERE "1st_leg"='1-3' AND "agg"='1-6';