Pipedrive shows you if you have a duplicate organization looking for other record  with similar phone or address. But this is not very accurate. My clients always ask for another way to check the duplicates. For example a unique Id. If I create a new organization with a unique ID such as tax ID, then when users want to create a new deal they can be sure if they need to create a new organization or its a duplicate. Because the tax ID its unique for each organization.