How to insert 1 or 0 in Sql Server for bit type field if checkbox is checked?

I am trying to insert 1 or 0 in my SQL Server Database, and my data type is "bit". I have tried doing this but it says incorrect syntax near where-
dt=g1.ExecDB(insert into tbl ("check1,check2,check3") values('"+Convert.ToByte(check1.Checked)+"','"+Convert.ToByte(check2.Checked)+"','"+Convert.ToByte(check3.Checked)+"')) where loginname='"+Session["log"].ToString()+"'"); Please guide me where I am doing wrong?