What is the Agg for 1st Leg 1-2 and 2nd leg of Withdrew?
CREATE TABLE "round_16_matches" (
  "team_1" text,
  "agg" text,
  "team_2" text,
  "1st_leg" text,
  "2nd_leg" text
);
SELECT "agg" FROM "round_16_matches" WHERE "1st_leg"='1-2' AND "2nd_leg"='withdrew';