What is the area (ha) of the group on the island of Linga Holm that has a Height (m) larger than 7?
CREATE TABLE "main_list" (
  "island" text,
  "group" text,
  "area_ha" text,
  "population" text,
  "height_m" real
);
SELECT "area_ha" FROM "main_list" WHERE "height_m">7 AND "island"='linga holm';