Name the years when decile was less than 7 for waitoa school
CREATE TABLE "matamata_piako_district" (
  "name" text,
  "years" text,
  "gender" text,
  "area" text,
  "authority" text,
  "decile" real,
  "roll" real
);
SELECT "years" FROM "matamata_piako_district" WHERE "decile"<7 AND "name"='waitoa school';