Asp - Aspartic acid
The genetic code chart can be read to determine which amino acid is designated by the codon GAC.
The first base of the codon is read along the left side of the chart - this puts the amino acid in the 4th row.
The second base is read along the top of the chart. This puts the amino acid in the 3rd column of the chart.
The last base is read along the right side of the chart - this tells us this codon codes for the second amino acid down in the third box of the fourth row of the chart.
You probably noticed reading the chart that the codon GAU would code for the same exact amino acid.
This video might also be helpful for understanding the process of transcription and translation.
Hope this helps!