title: The `hue` parameter in Seaborn.relplot() skips an integer when given numerical data?
body: <p>The hue parameter skips one integer.</p>
  
  <pre><code>d = {'column1':[1,2,3,4,5], 'column2':[2,4,5,2,3], 'cluster':[0,1,2,3,4]}
  
  df = pd.DataFrame(data=d)
  
  sns.relplot(x='column2', y='column1', hue='cluster', data=df)
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/w8eNn.png" rel="noreferrer"><img src="https://i.stack.imgur.com/w8eNn.png" alt="While all points are plotted, the cluster label is missing &#39;2&#39;."></a></p>
  
  <p><em>Python 2.7
  Seaborn 0.9.0
  Ubuntu 16.04 LTS</em></p>