CREATE TABLE table_23346 ("Rank" FLOAT, "City" TEXT, "1890 census" TEXT, "1910 census" FLOAT, "1920 census" FLOAT, "1930 census" FLOAT, "1940 census" FLOAT)

For cities with a census of 296000 in 1940, what was their census in 1920?
SELECT "1920 census" FROM table_23346 WHERE "1940 census" = '296000'
SELECT "1920 census" FROM "table_23346" WHERE "1940 census" = '296000'