How to Implement table selection in Django ORM table field?

Question

Django

I came across the following task:
Implement the main table with the fields title, date, description in which you can select another table with fields, but only one. In the main table, select a category with a set of fields.

class BaseTable(models.Model):
    title = models.CharField(max_length=50)
    date = models.DateTimeField(auto_now_add=True)
    descriptions = models.TextField()


class A(models.Model):
    bed = models.CharField(max_length=50)
    height = models.CharField(max_length=50)
    base_ads = models.OneToOneField('BaseTable', on_delete=models.CASCADE, related_name='a')


class B(models.Model):
    mat = models.CharField(max_length=50)
    quality = models.CharField(max_length=50)
    size = models.CharField(max_length=50)
    base_ads = models.OneToOneField('BaseTable', on_delete=models.CASCADE, related_name='b')

Maybe there is a better way to connect them and implement a choice?