AFAIK, neither one of them has made a diesel car for sale in the US (at least not in the last 20 years).
For diesels you're looking at VW, Mercedes, some old GM boats (from the '80s), and big pick-ups (and a very few odd imports).
Consider a small light car like an old Nissan Sentra if you're looking for inexpensive and good mileage.
Luck with the search!
Cheers,
Scott.