Go to Contacts> Menu> View.. and you can check/uncheck which accounts you want showing (phone, facebook, google, etc..).
If you have duplicates from both Phone and Google and you want to delete the phone contacts..
Contacts >Menu >View >Make sure just "Phone" is checked >Press OK >Menu >Delete contacts >Menu >Select All > Done..
Then press Menu >View >Select Google and whatever other accounts you want showing again.