[Answered ]-Django select how to remember chosen value?

Change your template select options to:

<option value="{{ item.id }}"
{% ifequal teacher_id item.id %}selected{% endifequal %}
>{{ item.title}} {{ item.name }} {{ item.surname }}</option>

It will test if the the option id is equal to teacher_id, and add the selected tag if true.

the same for option 0:

<option value="0" {% ifequal teacher_id 0 %}selected{% endifequal %}>blank</option>