Which population is the greatest, has a density of 20.3, and an area (km²) larger than 50,350?
CREATE TABLE "by_density" (
  "rank" text,
  "state" text,
  "population" real,
  "area_km" real,
  "density" real
);
SELECT MAX("population") FROM "by_density" WHERE "density"=20.3 AND "area_km">'50,350';