What's the highest against score that drew more than 5, and had more than 18 points?
CREATE TABLE "campeonato_paulista" (
  "position" real,
  "team" text,
  "points" real,
  "played" real,
  "drawn" real,
  "lost" real,
  "against" real,
  "difference" text
);
SELECT MAX("against") FROM "campeonato_paulista" WHERE "drawn">5 AND "points">18;