CREATE TABLE table_79737 ("Number" FLOAT, "Builder" TEXT, "Built" TEXT, "Rebuilt" TEXT, "Name as rebuilt" TEXT, "Scrapped/Sold" TEXT)

Which Rebuilt has a Builder of derby, and a Name as rebuilt of ben madigan?
SELECT "Rebuilt" FROM table_79737 WHERE "Builder" = 'derby' AND "Name as rebuilt" = 'ben madigan'
SELECT "Rebuilt" FROM "table_79737" WHERE "Builder" = 'derby' AND "Name as rebuilt" = 'ben madigan'