WordPress provides is_paged() which returns true on any archive or blog that stretches over multiple pages. This isn’t what you want, but the is_paged Codex article tells us where to go:
If you need to check which page of the blog you are on, you can look in $wp_query->query_vars[‘paged’]. Remember that inside functions you might have to global $wp_query first.
So, you should be able to use this snippet to only show something on the first page:
global $wp_query;
$my_paged_page = $wp_query->query_vars['paged'];
if ( $my_paged_page == 1 ) {
// do something
}