b prefixo significa literal de byte em Python3. Tente convertê-lo em string.
...
res = (b'1', b'2015-01-02 23:11:19', b'25.00')
new_res = []
for i in res:
new_res.append(i.decode(encoding='utf-8'))
new_res = tuple(new_res)
...
...
res = (b'1', b'2015-01-02 23:11:19', b'25.00')
new_res = []
for i in res:
new_res.append(i.decode(encoding='utf-8'))
new_res = tuple(new_res)
...