if statements are not working as expected python 3.4.0 [duplicate]

So I've been working on a login program that takes the user input and responds differently for every different user input inputted.

if str(Username) != 'Exit' or ' exit' or 'login' or 'Login':
    print('Welcome')
    Create_profile()
    Write_Password()
    Write_Username()
    Read_Username()
    Read_Password()

    print('So your username is '+str(Username)+' and your Password is '+str(Password)+'.')
    print('Data successfully saved. Thank you.')

elif str(Username) == 'Exit'or'exit':
    print('exiting.')

elif str(Username) == 'Login' or 'login':
    print('Logging in......')
    Login_Sequence()
    print('2') 

Every time I run this and input 'Login' or login' or 'exit' or 'Exit' this thing somehow tells me that 'login' is my Username. Which is not what I want.