What is the average area with valparaíso as the capital?
CREATE TABLE "list_of_provinces" (
  "region" text,
  "province" text,
  "capital" text,
  "no_of_communes" real,
  "area" real,
  "2002_population" real
);
SELECT AVG("area") FROM "list_of_provinces" WHERE "capital"='valparaíso';