SPOT IS WRITTEN AS 1234,CAUGHT IS 567894 THEN SMART-?

SMART is written as 10604.

From the word SPORT and CAUGHT it can be concluded that the alphabets and numbers follow a particular sequence. For example, for both the words the letter T uses the number 4. Therefore for S it should be 1and for A it should be 6. As for the letters M and R there r no numbers prescribed when comparing the three words. Therefore we can prescribe the number 0 to them. Another reason for this is that, both the words have already chosen all the one digit numbers from 1-9 and the only remaining one is 0. So logically it could and may be 0.

I hope my answer helps.