What school in Dalefield has a roll less than 81?
CREATE TABLE "carterton_district" (
  "name" text,
  "years" text,
  "gender" text,
  "area" text,
  "authority" text,
  "decile" real,
  "roll" real
);
SELECT "name" FROM "carterton_district" WHERE "roll"<81 AND "area"='dalefield';