What is listed for the Province with a Wamalwa of 4,431?
CREATE TABLE "by_province" (
  "province" text,
  "kibaki" text,
  "raila" text,
  "wamalwa" text,
  "ngilu" text,
  "others" text,
  "registered_voters" text,
  "turnout_pct" text
);
SELECT "province" FROM "by_province" WHERE "wamalwa"='4,431';