Creating a choice in Python [duplicate]

This question already has an answer here:

• How to test multiple variables against a value? 17 answers

started coding in Python very recently and extremely fresh.

I'm trying to create a miles to km or km to miles converter.

The conversion part works and returns the value after the user inputs it.

choice = raw_input("Press 1 to convert Miles to KM or 2 for KM to Miles: ")
valid = ("1" or "2")

while choice in valid:
    if choice == "1":
        milesInput = float(raw_input("Enter the amount of miles:\n"))
        print ("The total KM is: ")
        print milesInput * 1.609
    elif choice == "2":
        kmInput = float(raw_input("Enter the amount of kilometres: \n"))
        print ("The total miles is: ")
        print kmInput * 0.621

If i enter the choice as "2" - it just finishes the code despite the condition being true.

Any advice is greatly appreciated. What am i doing wrong?