When Server-Side-Processing: How to render Column Data ?

How can i render Columns Data, when using ssp-class ?

I tried to render the column Array, like i do within my editor Examples, but this doesn't work here.

var thisDataTable = $('table').DataTable( {
    ajax:     'ssp-script.php',

// (!) doesn't work here 
columns: [
    { 
    data:  null, 
    defaultContent: ''
  },

    { 
    data: 'last_name',  
    className: '-text-left -text-bold' 
  },

    { 
    data: 'first_name',  
    className: '-text-left -text-bold' 
  },

    { 
    data: 'position',  
    className: '-text-left' 
  },
],