title: Access 1st column in Pandas dataframe
body: <p>How do I access the first column in this dataframe? 
  If I refer to it by the column name ('Group11...'), I get an error 'Not in index'.</p>
  
  <p><a href="https://i.stack.imgur.com/Od4ZG.jpg" rel="nofollow noreferrer">First Column</a></p>