Jetpack by WordPress.Com provides you a mobile theme that you can activate from Jetpack’s main page in your WordPress admin area dashboard. By default most plugins that allows you to select positions for displaying ads like Google Adsense works only in main activated theme of your WordPress site. Hence, your blog readers who visit your site from their mobile devices get none of your ads displayed.
This tutorial explains you how you can easily display Ads on Jetpack’s mobile theme. First of all you have to install and activate Jetpack Mobile Theme Ads. After activation visit Dashboard -> Settings -> Mobile Ads Settings. Now you have to enter your Google Adsense Mobile Banner information. So copy and paste Client ID, Slot ID, Width and Height from your Google Mobile Banner Ad Code.
This plugin is still developing so in the near future its developers might provide you with more useful features and customization options. You can report issues here, or submit a pull request on GitHub.
Second Method (By hacking Jetpack Mobile Theme): Alternatively, if you like digging with your website code then you can visit your website vis FTP and open this location /public_html/wp-content/plugins/jetpack/modules/minileven/theme/pub/minileven Now find content.php file and add your Ad Code wherever you want your ad to appear.