Not the most elegant way, but it is working:
DateTime now = DateTime.Now;
if(
(now.DayOfWeek == DayOfWeek.Monday && now.TimeOfDay >= TimeSpan.Parse("10:30"))
|| (now.DayOfWeek > DayOfWeek.Monday && now.DayOfWeek < DayOfWeek.Wednesday)
|| (now.DayOfWeek == DayOfWeek.Wednesday && now.TimeOfDay <= TimeSpan.Parse("11:00"))
)
{
Console.WriteLine("1");
}
else
{
Console.WriteLine("0");
}