SQLite Forum

It would be perfectly fine to enclose D3 in DOUBLE quotes "D3", Things in double quotes will always be seen as an identifier (like table or column name) assuming that is a valid by the context, even if the contents of the double quote would otherwise not qualify.

You could defensively double quote ALL such identifiers in a statement and never get an issue. 

The only case where they could give you a problem if you used them in a context where an identifier was not allowed, but a string was.