CREATE TABLE table_46497 ("Railway" CLOB, "Builder" CLOB, "Built" FLOAT, "Wheels" CLOB, "Location" CLOB, "ObjectNumber" CLOB)

Which Built has a Builder of brel crewe?
SELECT AVG("Built") FROM table_46497 WHERE "Builder" = 'brel crewe'
SELECT AVG("Built") FROM "table_46497" WHERE "Builder" = 'brel crewe'