Set Value to "0" if entity is not Available

Configuration
21

So, here is my solution:

value_template: >          
          {% if  is_state('sensor.aeg_waschmaschine_wm1_cyclephase', 'unavailable') %}
          keine
          {% elif is_state('sensor.aeg_waschmaschine_wm1_cyclephase', '') %}
          keine
          {% else %}
          {{ states('sensor.aeg_waschmaschine_wm1_cyclephase') }}
          {% endif %}

It works perfectly.