PHP code to display block based on list (text) field
With the following script you can check the value and return true. I've added my comments before each line.

// First check if the current page is a node
if ($node = menu_get_object()) {
 // Then, check if it is your content type
 if ($node-&gt;type == 'your_content_type') {
   // Get the value of your field
   $display_block = field_get_items('node', $node, 'field_display_block');
   // If the field's value is equal to 1, then return true
   if ($display_block[0]['value'] == '1') {
     return TRUE;
   }
  }
}