SQL (in the form of MySQL)
is supported on Free Hosting. MS SQL Server is not -- but your code should never be hard-coded to a particular relational database in any case. That means using things like PDO in PHP, and ADO.NET or LINQ in your .NET code, and accessing and modifying data through custom classes that remove proprietary SQL syntax from the main body of your code.
ASP.NET (*.aspx) is supported on Premium Hosting via Mono, which is not 100% compatible with Windows-based ASP.NET. It covers all of the ECMA-235 (the open standard CLI), most of Framework 2.0 (minus, of course, the Windows-specific system calls), parts of Framework 2.5 and parts of MVC and AJAX. You would need to check the
Mono Project site for code compatibility and documentation.
ASP (classic VBScript-based ASP) requires Windows hosting, which is almost never free -- the operating system licensing costs alone make free offerings rare.