the 0 folder is an emulated partition of the internal storage on your phone. i have one too. everyone does.
if you go into es file explorer, and go to the root of you phone, and then hit storage, you will see 3 options, "emulated", "sdcard1" and "0"
the "0" is a fake sd card. the internal storage is partitioned, in case something goes wrong you wont lose all your data.
i found this out the hard way lol forgot to back up and data wipe before flashing a rom once when i was half asleep, and you would think its all gone but no it was still all there. games, apps, contacts, the whole 9.