Why is from code import * different from entering that code directly into the REPL?

[sebi]

...indeed, for code.py being

a = 0
def func():
    global a
    a = 1

after entering that code directly into the REPL and typing

func()
print(a)

I get 1, while I get 0 after a

from code import *

Why? Dear community, I am a noob looking forward to understanding such different behaviors. Any help would be greatly appreciated.