Markdown filter over first x characters

Hello,
I would like to do a filter over the first 14 charakters of the attributes

{% if is_state_attr('sensor.ical_adler_gameday_event_7', 'summary', 'Adler Mannheim ') %}

in the attributes summary is for examble:
Adler Mannheim vs. Nürnberg Ice Tigers

The If query should only output the values ​​if the first 14 characters are Adler Mannheim in the summary

I Don’t know how to change the code.

I think you need to do like this:

{% if state_attr('sensor.ical_adler_gameday_event_7', 'summary')[0:14] == 'Adler Mannheim' %}

thanks it works

I don´t know why, but now the code don´t work anymore.

In the summary stands for example:

summary: 'Adler Mannheim vs. Eisbären Berlin ’

and with this code:

  {% if state_attr('sensor.ical_adler_gameday_event_0', 'summary')[0:14] ==
  'Adler Mannheim' %}

It don´t show anything.

Have anyone an idea why it don´t work anymore?