With the release of MDT 2013 Update 1 (build 8298) Microsoft pulled the download for the old MDT 2013 (without Update 1, build 5019)
But MDT 2013 build 5019 is still available for download if you know where 🙂
http://download.microsoft.com/download/B/F/5/BF5DF779-ED74-4BEC-A07E-9EB25694C6BB/MicrosoftDeploymentToolkit2013_x64.msi (link via Wayback Machine, Internet Archive)
MDT 2013 also uses Windows ADK 8.1 which you find here:
http://www.microsoft.com/en-us/download/details.aspx?id=39982

How about for MDT 2012 Update 1?
Sorry, that one has been removed.