CREATE TABLE table_name_88 (population__1931__in_1 VARCHAR, capital VARCHAR)

Capital of brze nad bugiem has what population (1931) in 1,000s?
SELECT population__1931__in_1, 000 AS s FROM table_name_88 WHERE capital = "brześć nad bugiem"
SELECT "population__1931__in_1", 000 AS "s" FROM "table_name_88" WHERE "brześć nad bugiem" = "capital"