Software that can be used for conversion of odg file type to docx format.
Search for odg to docx converter or software able to handle these file types.
Some online conversion services like ZAMZAR claim that they can convert OpenDocument Drawing files (.odg) to Microsoft Word document (.docx), which is what odg to docx conversion represents.
As these files serve different purpose, it is likely that what the "conversion" does, is that it creates a Word document where on one of its pages the drawing or drawings from *.odg files are pasted. Not exactly conversion, but probably the only way how to achieve this.
An odg file suffix is associated with the Object-based Visual Application Language developed by Psion.