Do,
<?php if( false == get_post_format() ){ ?>
<a href="https://wordpress.stackexchange.com/questions/103119/<?php the_permalink(); ?>" rel="bookmark"><?php the_title(); ?></a>
<?php } ?>
The standard post format isn’t actually a post format, so if you conditionally check whether a post contains a post format (other than the default standard), it will return false
, because it’s set to… standard.