What is the lowest number of sunlight hours, and number of days with frost, more than 30, for the city of Ourense?
CREATE TABLE "climate" (
  "city_town" text,
  "july_av_t" text,
  "rain" text,
  "days_with_rain_year_summer" text,
  "days_with_frost" real,
  "sunlight_hours" real
);
SELECT MIN("sunlight_hours") FROM "climate" WHERE "city_town"='ourense' AND "days_with_frost">30;