CREATE TABLE table_22481967_1 (builder VARCHAR, withdrawn VARCHAR, number VARCHAR)

List the number of builders where the withdrawn is 1951 and number is 42.
SELECT COUNT(builder) FROM table_22481967_1 WHERE withdrawn = "1951" AND number = "42"
SELECT COUNT("builder") FROM "table_22481967_1" WHERE "1951" = "withdrawn" AND "42" = "number"