In MATLAB, the colon operator indicates the range of values that are used for an operation.
lowestNum:HighestNum is the general usage.
In the case of 0:0.1, the lowest number is 0, the step size is 1 (by default) and the last number is 0.1. Since, its a valid range, the value of 0 is printed.
In case of 1:0.1, the lowest number is 1, the step size is 1 (by default) and last number is 0.1. Since, 1 cannot be made to 0.1, with a step size of 1, the value returned is empty.
You can try 1:-1:0.1, then the first value of 1 is printed, since there is a step size of -1 and it can go near 0.1.
For more information about colon operator, look here.
Hope this helps.