How to leave Choices field with no default value

Question

I currently have this class with a field Choice, tried to leave by default "deufault=None" can it remains bringing the field filled with Royal Flush, if I move to another existing City he accepts, I’m doing something wrong?

class Sessao(models.Model):
    MAO_DERROTA = (
        ('Royal Flush', 'Royal Flush'),
        ('Straight Flush', 'Straight Flush'),
        ('Quadra', 'Quadra'),
        ('Full House', 'Full House'),
        ('Flush', 'Flush'),
        ('Straight', 'Straight'),
        ('Trinca', 'Trinca'),
        ('Dois pares', 'Dois pares'),
        ('Um Par', 'Um Par'),
        ('Carta Alta', 'Carta Alta'),

    )
    data_ini_sessao = models.DateField(verbose_name='Data inicial da partida')
    torneio = models.ForeignKey(Torneio, verbose_name='Torneio', on_delete=models.CASCADE)
    buy_in = models.DecimalField(max_digits=10, decimal_places=2,verbose_name='Buy-in')
    jogadores = models.IntegerField(verbose_name='Qtd jogadores')
    premio = models.DecimalField(max_digits=10, decimal_places=2,verbose_name='Vlr Premio')
    saldo = models.DecimalField(max_digits=10, decimal_places=2,verbose_name='Saldo da partida')
    colocacao = models.IntegerField(verbose_name='Colocação')
    data_fin_sessao = models.DateField(verbose_name='Data final da partida')
    user = models.ForeignKey(User, on_delete=models.CASCADE)
    tempo = models.IntegerField(verbose_name='Tempo')
    comentario_sessao = models.TextField(blank=True)
    mao_derrota = models.CharField(max_length=50, choices=MAO_DERROTA, default=None)

Answer 1

Alter MAO_DERROTA for:

MAO_DERROTA = (
    ('','..........'),  
    ('Royal Flush', 'Royal Flush'),
    ('Straight Flush', 'Straight Flush'),
    ('Quadra', 'Quadra'),
    ('Full House', 'Full House'),
    ('Flush', 'Flush'),
    ('Straight', 'Straight'),
    ('Trinca', 'Trinca'),
    ('Dois pares', 'Dois pares'),
    ('Um Par', 'Um Par'),
    ('Carta Alta', 'Carta Alta'),
)

Change the dots (.......), for whatever you want.