You should replace the string:
if low_original[0] == 'a' or 'e' or 'i' or 'o' or 'u':
with:
if low_original[0] in ('a', 'e', 'i', 'o', 'u'):
The result of the line
'a' or 'e' or 'i' or 'o' or 'u'
is one str - 'a', so you just have
if low_original[0] == 'a'