In the SD card slot on what? Not all SD card reader/writers connect the card detect pin to anything. You'd need to do that if it hasn't been done, and read the pin you connect it to just like any other pin.
did you mean CD pin ?
CD as in Card Detect. Yes, that is the one I meant.
can i connect SD shield & RTC (real time clock)Shield with Arduino Due , i mean Arduino Due compatible with SD card & RTC Shield
Depends on the shields. If there are no pin conflicts (conflicts seem unlikely), then yes.