The problem is that that's an SQL command - so double quotes aren't applicable anyway, unless you want them as part of an actual string.
SQL uses single quotes for string delimiters, not double quotes, so to return a string literal all you would do is surround it with double quotes:
SELECT 'Hello world!';
If you are trying to "build a query" and return a column called
then you need to use either square brackets (SQL Server) or backquotes (Access):
SELECT [Provider Review] FROM MYTable
But the Query you show doesn;t make it at all obvious what exactly you want - it isn't valid SQL at all because Distinct is a keyword which needs to be followed by a column name rather than a comma.
If you need to put double quotes in a C# string literal, there are two ways
1) Escape it:
string s = "this is surrounded by \"double quotes\"";
2) Escape the string and double them:
string s = @"this is surrounded by ""double quotes""";