Validation checking

[Help_me_Please]

I am stuck in a loop where I cannot move onto player 2 selection. (im in the early stage and I am only onto the validation checking so far):

import numpy as np
turn = 0
game_over = False

def board_create(column, row):
    board = np.zeros((row,column))
    return board

def is_valid_location(column_choice, board, bottom_row):
    if board[bottom_row][column] == 0:
        return False
    else:
        return True

row = 5   
#row = int(input("How many rows: "))
column = int(input("How many columns: "))
board = board_create(column, row)

while not game_over:
    if turn == 0:
        invalid = True
        bottom_row = 0
        while invalid == True:
            column = column - 1
            column = str(column)
            column_choice = int(input("Player 1 make your selection (0-"+column+"):"))
            column = int(column)
            invalid = is_valid_location(column_choice, board, bottom_row)
            column = column + 1
    else:
        while invalid == True:
            column = column - 1
            column = str(column)
            column_choice = int(input("Player 2 make your selection (0-"+column+"):"))
            column = int(column)
            invalid = is_valid_location(column_choice, board, bottom_row)
            column = column + 1
    turn = turn + 1
    turn = turn % 2

Would be thankful for any help given