No one said the 12F683 can't do the job. It can.
Charlie implied that you could store your value in the FLASH memory - which you can, as a non changeable constant of course - but if you need to be able to change it and store it during runtime, which is what you're asking about then the FLASH memory can't be used because the 12F series lack the abillity to write to its own FLASH memory.

The EEPROM on the other hand will work just fine. Look at READ and WRITE in the manual.

/Henrik.