You can use integrators as counters. Check for your desired state (TRUE or FALSE), then convert this TRUE signal into a double/single value, and feed it into an integrator. Then all you have to do is check when your output reaches your desired value (0.1 seconds).
Make sure you set the correct sample time (if using a discrete system), and also initialise/reset your integrator to zero.
If you need it to be constantly true for a time then just reset your integrator when you have an undesirable input.
For example, the output for this system will be true if the input has been FALSE for at least 0.1 seconds:
