This Way:

I have bind the time with dummy table data you can bind the datalist from SQL:

HTML:

<form id="form1" runat="server">
    <div>
        <asp:DataList ID="DataList1" runat="server" OnItemDataBound="DataList1OnItemDataBound">
            <HeaderTemplate>
                <table border="0" cellpadding="5" cellspacing="0">
                    <tr>
                        <td>
                            Name
                        </td>
                        <td>
                            Time
                        </td>
                    </tr>
            </HeaderTemplate>
            <ItemTemplate>
                <tr>
                    <td>
                        <asp:Label ID="lblName" Text='<%# Eval("Name") %>' runat="server" />
                    </td>
                    <td>
                        <asp:Label ID="lblTime" Text='<%# Eval("Time", "{0:hh:mm:ss}") %>' runat="server" />
                    </td>
                </tr>
            </ItemTemplate>
            <FooterTemplate>
                </table>
               Total time: <asp:Label ID="lblTotal" runat="server" />
            </FooterTemplate>
        </asp:DataList>
    </div>
    </form>

C#:

int h = 0;
    int m = 0;
    int s = 0;
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!this.IsPostBack)
        {
            DataTable dt = new DataTable();
            dt.Columns.AddRange(new DataColumn[2]{new DataColumn("Name",typeof(string)),
                                new DataColumn("Time",typeof(DateTime))});
            dt.Rows.Add("Azim", DateTime.Now.ToString("hh:mm:ss"));
            dt.Rows.Add("Sajid", DateTime.Now.ToString("hh:mm:ss"));
            dt.Rows.Add("Amir", DateTime.Now.ToString("hh:mm:ss"));
            DataList1.DataSource = dt;
            DataList1.DataBind();
        }
    }
    protected void DataList1OnItemDataBound(object sender, DataListItemEventArgs e)
    {
        if (e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem)
        {
            string t = ((Label)e.Item.FindControl("lblTime")).Text;
            h += Convert.ToInt32(t.Substring(0, 2));
            m += Convert.ToInt32(t.Substring(3,2));
            s += Convert.ToInt32(t.Substring(6, 2));
        }

        if (e.Item.ItemType == ListItemType.Footer)
        {
            Label lblTotal = (Label)e.Item.FindControl("lblTotal");

            lblTotal.Text = h.ToString() + " : " + m.ToString() + " : " + s.ToString();
        }
    }

Image:

Thank You.