from django.db import models

class Priority(models.Model):
    name = models.CharField(max_length=100)

class Tasks(models.Model):
    name = models.CharField(max_length=30)
    description = models.CharField(max_length=40)
    priority = models.ForeignKey(Priority)

tasks = Tasks.objects.all() #запрос

{% for t in tasks %} 
    name: {{t.name}}
    description: {{t.description}}
    priority: **{{t.priority.name}}** {# запрос #}
{% endfor %}

class User(Base):
    __tablename__ = 'users'

    id = Column(Integer, primary_key=True)
    name = Column(String)
    fullname = Column(String)
    password = Column(String)

    def __init__(self, name, fullname, password):
        self.name = name
        self.fullname = fullname
        self.password = password

    def __repr__(self):
        return "<User('%s','%s', '%s')>" % (self.name, self.fullname, self.password)

class Address(Base):
    __tablename__ = 'addr'
    id = Column(Integer, primary_key=True)
    email_address = Column(String, nullable=False)
    user_id = Column(Integer, ForeignKey('users.id'))

    user = relation(User, backref=backref('addr'))

    def __init__(self, email_address):
        self.email_address = email_address

    def __repr__(self):
        return "<Address('%s')>" % self.email_address

users = session.query(User, Address).select_from(join(User, Address)).all()