Employees have no control over the assets in their Defined Benefit plan.
The short and simple answer is: No.
The payments you will receive in retirement are calculated according to a pre-determined formula. Your employer is responsible for managing the investments, while you simply receive the agreed-upon payments when they are due to you - assuming all goes as planned.
Most pension funds, as they are sometimes called, are invested in very conservative instruments such as long term government bonds and fixed accounts offered by some insurance companies and banking institutions.
Many forms of institutional investments may be available to an employer or the financial institution which serves as custodian of the funds. The employer and the custodians have a fiduciary responsibility to serve the best-interests of the employees.
Can Something Happen to My Defined Benefit Plan?
Where do I Get Started in Saving for Retirement?