There is no explanation to this but the least number is 0
because 1294 divided 9,11,13 will have remainder 7
some interesting fact
1293 divided by 9,11,13 will have same remainder 6
1292 divided by 9,11,13 will have same remainder 5
similarly
1291 -> 4
1290->3
1289->2
1288->1
1287-> 0
reason
remainder will be either 0 or 1 or 2 .. 8 cannot exceed 8
now 9*11*13= 1287 so divide it by 9 or 11 or 13 remainder will be 0
1288 = 1287 +1 hence remainder will be 1
1289= 1287+ 2 hence remainder will be 2 and so on till 1294
another interesting thing is 1294 +1 =1295 will be last number ot this series to have common remainder which would be 8