CREATE TABLE table_203_640 (id NUMBER, "name" CLOB, "college" CLOB, "years" CLOB, "reign" CLOB)

how long was harald v of norway the king of norway at the university of oxford ?
SELECT "years" - "years" FROM table_203_640 WHERE "name" = 'harald v of norway'
SELECT "years" - "years" FROM "table_203_640" WHERE "name" = 'harald v of norway'