CREATE TABLE table_203_212 (id DECIMAL, "#" DECIMAL, "district" TEXT, "land area  ( km2 ) " DECIMAL, "population\ ( 2010 census ) " DECIMAL, "density  ( persons/km2 ) " DECIMAL)

which other districts besides castries has a population that is more than 20,000 ?
SELECT "district" FROM table_203_212 WHERE "district" <> 'castries' AND "population\n(2010 census)" > 20000
SELECT "district" FROM "table_203_212" WHERE "district" <> 'castries' AND "population\n(2010 census)" > 20000