Neither of them support Python 3 but upcoming [1] Django 1.3 will have an experimental support. Luckily you can also other than web stuff on Heroku.

[1] https://www.djangoproject.com/weblog/2012/mar/13/py3k/

I think you mean Django 1.5, Django 1.3 came out a couple of years ago.

I did, thinking of Python 3 messed up my brain.

Django 1.5 should be released any day now, which adds support for Python 3!