Statistics And Machine Learning toolbox did not have 'Machine Learning' as part of its name back then, but it was the same product.
If you do not already have a license for that toolbox for that release or newer, then you would need to bring your MATLAB license up-to-date with support contracts (or by a new copy) before being permitted to purchase the toolbox.
If you have a Standard (Professional / Commercial) license, then if you have a license for the toolbox for that release or newer, go to https://www.mathworks.com/downloads/web_downloads/get_release?release=R2013a and download the installer and run; the installation process will ask you which of your licensed toolboxes to install.
For other licenses, see https://www.mathworks.com/matlabcentral/answers/389087-gostaria-de-adquirir-a-versao-r13-matlab-6-5-isto-e-possivel#answer_310567
For emphasis: it is not permitted to buy a license for a toolbox that old. There is only a limited period during which toolboxes can be purchases for older licenses.
