<?php if ( $paged < 2 ) {
// Do stuff specific to first page
?>
<?php if ( is_category() ) : ?>
<div id="h-description">
<h2 id="category-name-header">
<?php single_cat_title(); ?>
</h2>
</div>
<?php add_filter('category_description', 'wpautop'); ?>
<?php add_filter('category_description', 'wptexturize'); ?>
<div id="category-description">
<?php echo category_description(); ?>
</div>
<?php endif; ?>
<?php } else {
// Do stuff specific to non-first page
?>
<?php } ?>