CREATE TABLE table_21742 ("Number" CLOB, "Builder" CLOB, "Type" CLOB, "Date built" CLOB, "Heritage" CLOB, "Disposition" CLOB, "Notes" CLOB)

Name the disposition for date built is march 1909
SELECT "Disposition" FROM table_21742 WHERE "Date built" = 'March 1909'
SELECT "Disposition" FROM "table_21742" WHERE "Date built" = 'March 1909'