New domain but old indexed posts

Hi. I bought a new domain name and started posting on it. Today I wanted to see if Google indexed any of my pages but I saw the search engine indexed some pages that aren't currently on my website. I would like them to disappear because it's a different language and (maybe) different niche.

Will they disappear ? When ?

 

You can apply to have the pages de-indexed in Google Webmaster tools.

 

if at the moment these pages are not available for search engines (return 404 Error code), just wait a little time and they surely disappear.