Who is team 1 where team 2 is Fluminense (RJ)?
CREATE TABLE "round_of_sixteen" (
  "team_1" text,
  "agg" text,
  "team_2" text,
  "1st_leg" text,
  "2nd_leg" text
);
SELECT "team_1" FROM "round_of_sixteen" WHERE "team_2"='fluminense (rj)';