Check to see if anything has been entered into the_content();
<?php $page_content = get_the_content(); //Need to use get_the_content if using the_content in a conditional
if($page_content!=''){ ?>
<?php the_content(); ?>
<?php } else { ?>
<p>This displays if the_content is empty.</p>
<?php }; wp_reset_postdata(); //Ends the conditional and resets the post data ?>