What is the highest decile value with a roll greater than 301 in Hauraki?
CREATE TABLE "devonport_takapuna_local_board" (
  "name" text,
  "years" text,
  "gender" text,
  "area" text,
  "authority" text,
  "decile" real,
  "roll" real
);
SELECT MAX("decile") FROM "devonport_takapuna_local_board" WHERE "roll">301 AND "area"='hauraki';