CREATE TABLE table_204_257 (id DECIMAL, "ethnicity" TEXT, "1926 census" TEXT, "1939 census" TEXT, "1959 census" TEXT, "1970 census" TEXT, "1979 census" TEXT, "1989 census" TEXT, "2007 estimate" TEXT)

which population had the most people in 1926 ?
SELECT "ethnicity" FROM table_204_257 ORDER BY "1926 census" DESC LIMIT 1
SELECT "ethnicity" FROM "table_204_257" ORDER BY "1926 census" DESC NULLS LAST LIMIT 1