You can use next():
>>> a = [None, None, None, 1, 2, 3, 4, 5]
>>> next(item for item in a if item is not None)
1
If the list contains only Nones, it will throw StopIteration exception. If you want to have a default value in this case, do this:
>>> a = [None, None, None]
>>> next((item for item in a if item is not None), 'All are Nones')
All are Nones