Here's the deal. Theoretically anything is possible. However there does not yet exist a working or even close to stable "Original Xbox" emulator. Therefore playing ISO copies of original xbox titles is not probable on either the 360 or the One
Playing backups of original XBox games on the 360 require your console to be hacked.
Best way is to RGH it, which allows you to play extracted Xbox games on the machine.
Note that not all games will work.