Hi Divya,
As it is mentioned in API, in content aggregation of Simple Form, if you use Label control it will start a new row.
JsDoc Report - SAP UI development Toolkit for HTML5 - API Reference - sap.ui.layout.form.SimpleForm
Instead you can use a Horizontal Layout to place all controls in one row and have to adjust the margins.
May be like this might help? JS Bin - Collaborative JavaScript Debugging
Regards,
Sai Vellanki.