What is the average number conceded for hte team that had less than 19 points, played more than 18 games and had a position less than 10?
CREATE TABLE "torneo_apertura" (
  "position" real,
  "team" text,
  "played" real,
  "wins" real,
  "draws" real,
  "losses" real,
  "scored" real,
  "conceded" real,
  "points" real
);
SELECT AVG("conceded") FROM "torneo_apertura" WHERE "points"<19 AND "position"<10 AND "played">18;