What is the lowest value for Perth, when Melbourne is greater than 461,000, and when Sydney is less than 430,000?
CREATE TABLE "ratings" (
  "episode_number_production_number" text,
  "title" text,
  "sydney" real,
  "melbourne" real,
  "brisbane" real,
  "adelaide" real,
  "perth" real,
  "total" real,
  "weekly_rank" real,
  "nightly_rank" real
);
SELECT MIN("perth") FROM "ratings" WHERE "melbourne">'461,000' AND "sydney"<'430,000';