Normally FOR options are enclosed within quotes. If you want to use a quote as part of an option, then the enclosing quotes must be ditched. That means all characters that the CMD interpreter uses as token delimiters must be escaped, including space and equal sign. Also the quote needs to be escaped.
for /f tokens^=1^-3^ delims^=^" %F in ('echo "ab" "bc"') do echo f=%F g=%G h=%H
C:\Windows\System32>for /f tokens^=1^-3^ delims^=^" %F in ('echo "ab" "bc"') do echo f=%F g=%G h=%H
C:\Windows\System32>echo f=ab g= h=bc
f=ab g= h=bc
http://superuser.com/questions/514284/how-do-i-use-a-quote-as-a-for-f-delimiter-in-cmd-exe-on-windows-7