Tableau Professional is Tableau Desktop.
http://buy.tableausoftware.com/ shows two editions: Desktop Professional Edition and Desktop Personal Edition. Personal connects to "Excel, MS Access, or Text Files" and Professional connects to many other databases in addition.
They use the same file format. Anything created in Personal Edition can be opened in Professional Edition. Anything created in Professional Edition that connects to data sources that the Personal Edition is licensed for can also be opened in Personal Edition.
Hope that helps.